What is one reason why global warming is happening according to scientists?

Answer 1

Scientists believe it is happening because there is a growing body of evidence, including melting ice, changes in long-term weather patterns, a rise in global CO2 levels, etc. Essentially, they believe it because there is evidence.

Answer 2

Global warming means worldwide rise in temperature. In modern 20th century, the global warming has started tremendously because of the following factors :-

(i) Urbanization :- As the population increases, there will be more demand of resources and this causes global warming because when Natural Resources are limited in nature then temperature of earth increases like - due to deforestation (cutting of trees) as trees contribute in a large way in maintaining the water cycle. They take water from their roots and then the water is released into the atmosphere. of the water and this maintains balance of O2 & CO2 . When these trees are cut down it results in the climate getting drier in that area.

(ii) Greenhouse Effect :- Greenhouse gases like - CO2 , Methane , Chlorofloro Carbon (CFC), trap the infrared radiations that escapes from Earth and thus it makes the Earth warmer.

These are the big reasons for Global Warming.

In addition, scientists do not think that the global climate is changing. They can prove that it is. The debate is about which factors are most responsible for the change in climate. The most likely direct causes of Climate Change are:

• Melting of the ice caps - this raises ocean water levels, lowers the total albedo of the planet, decreases ocean salinity, and can alter ocean currents.
• Thinning of the Ozone layer - this increases solar radiation penetration to the Earth's surface
• Increased "greenhouse gas" concentrations in the atmosphere - this traps larger amounts of reflected infrared radiation, increasing atmospheric temperatures
• Increased particulates concentration in the atmosphere - larger amounts of soot, dust, and other particulate matter in the atmosphere alters both the amount of solar radiation absorbed by either the atmosphere or surface of the Earth, and also how much reflected radiation from the Earth can escape.
• Increase Solar activity - the Sun is pumping out more radiation than "normal" (in reality, it's just going through a typical solar cycle, and is on the "upswing" of radiation production) - the Earth thus absorbs more radiation than "typical", simply because more is being produced by the Sun.
• Slight variations in Earth orbit, due to cyclical changes - changes in the Earth's orbit result in differences in solar radiation absorption, and also changes in the Earth's magnetic field
• Changes in the Earth's Albedo (reflectivity) - these are due to a wide variety of causes, from changes in forest cover or ice/snow cover, to differences in cloud size and area, and from things such as urbanization (which alter the albedo of the surface, as concrete/asphalt are different colors than "natural" groundcover). A decreased albedo results in more solar energy being absorbed by the Earth (and, vice versa).

The problem is determining what exactly is causing the above, and how much each of the above contributes to Climate Change.

Answer 3

The burning of fossil fuels (coal, oil and natural gas) in industry, transport and the generation of electricity, which releases carbon dioxide (CO2). This is increasing the levels of CO2 in the atmosphere, causing global warming.